- get a conventional thermostat system, not one of those newfangled 'communicating' designs. 5 years down the line when the manufacturer stops making whatever 'board' died this week, you will be SOL with a communicating design. A conventional thermostat can still have features like Wifi and remote controls.
I decided the other way on this one mostly because after researching I found that Bryant and a couple of others (Carrier, etc... many of these brands have been bought up into a conglomerate and they're made in the same places anyway) built SOME of their communicating T-stat lines using a standard communications protocol. Not much risk of a "board" failure not being able to be replaced by a brand new t-stat down the road. It won't be the same physical t-stat, but it'll speak their standard protocol back to their devices. It's a risk, but it's about a $300 risk. And I love the Bryant t-stat. Great features, internet connectivity for free/life/whenever Bryant goes under... at least as good as a Nest.
He probably went upsize because the previous one wasn't doing its job. That and global warming.
LOL.
Make sure you have the best cold air return possible. I had one put in the basement (there was NONE down there). I used to have 65 degrees in the basement, 75 degrees main floor and 85 degrees second floor when it was 100 outside. And it wasnt the air conditioners fault. It was because the duct system was designed for heat (Colorado) and air conditioning was an afterthought. In southern climates they put air conditioning ducts coming out of the ceiling of the top floor. Well I couldnt do that but we figured out how to put a cold air return at the top of the top floor and a cold air return in the basement. I now have 70 degrees in the basement, 75 on main floor and 80 upstairs. Not bad and better than before. Still not perfect.
The comments about ductwork are CRITICAL in a retrofit. Our ductwork SUCKS in our house. We also had ZERO returns in our basement which is just stupidity. We did one winter in the original configuration and for better or worse a plumbing leak upstairs led to tearing out a finished basement ceiling and since our installer on the HVAC had said if we ever had to get into the ceiling to call them and they'd fix the return problem and anything else in the basement duct work that they could, we took them up on it and tore more of the ceiling out. Had to hire drywall folks anyway at that point so what's a few more bucks.
Our ductwork still Isn't quite right, but we got temps to stay within 5F of each other heating or cooling between floors.
Continuous fan also factors into this. In winter we run it a little faster and it does a great job of circulating heated air around the house. I'm not as concerned with using a fairly deep daily setback when nobody is home because I'm not as worried about temps in the bathrooms with outside walls.
Summer, we can shut it down in the profiles or leave it on very low speed and it's not as useful but it still helps even out things on a hot day between upstairs and basement.
We still have a static pressure problem even with more ductwork fixes but another plus of a variable speed system with a smart controller is that we can force CFM limits on a system that will blow much harder than the ductwork will allow and it'll compensate.
Oh. Forgot to mention. Doesn't apply to the heat pump setup but with ours being forced air propane, a variable BURNER (modulating as they say) is also installed with the variable blower. This allows the system to sip fuel at 40% of max heating power and vary the burner to match the CFM limitation forced by the ductwork.
This thing compared to the old stupid 80% efficient on/off furnace is like night and day. We love it.
